Field of the Invention
The present disclosure relates to a printed circuit board divided by a division process.
Description of the Related Art
As one of image defects in an image forming apparatus such as a laser beam printer, there is an image defect termed a “white spot of an image”. This image defect occurs by minute dirt adhering to an optical component (a lens or a mirror) in an exposure unit (also referred to as “scanner unit”) 9 of the image forming apparatus. Examples of the minute dirt include shavings of a printed circuit board on which a control circuit for controlling the operation of the exposure unit 9 is mounted.
For example, a description will now be given of a printed circuit board on which a light-emitting element driving circuit 10 of the exposure unit 9 is mounted, and the production of shavings of the printed circuit board. FIG. 3 is a view of a board member 31 on one surface (a component surface or a soldering surface) thereof. As illustrated in FIG. 3, the board member 31 is a single board from which printed circuit boards 32 (32a, 32b, 32c, and 32d) can be obtained as a plurality of surfaces. In FIG. 3, actually, a connection portion is provided between the printed circuit boards 32b and 32c, but is not illustrated. As illustrated in FIG. 3, the printed circuit boards 32 (32a, 32b, 32c, and 32d) are joined together by narrow joint portions 33, thereby forming the single board member 31. Further, slit portions 34 illustrated in FIG. 3 are hollow portions in the board member 31. The joint portions 33 (dotted line portions in FIG. 3) are cut with a router or the like in this state, thereby dividing the printed circuit boards 32 into single boards 32a, 32b, 32c, and 32d. When the joint portions 33 are cut with a router or the like, shavings are produced.
As described above, many lenses and mirrors are provided in the image exposure unit 9 of the image forming apparatus. If minute shavings adhere to the lenses and the mirrors, an image defect occurs. Thus, in a factory handling an optical unit such as the exposure unit 9, it is necessary to minimize the production of shavings.
As a method for reducing shavings produced when a printed circuit board is cut, Japanese Patent Application Laid-Open No. 2007-88232 is known. Japanese Patent Application Laid-Open No. 2007-88232 discusses a configuration in which, after a printed circuit board is cut, a resist is applied to cover the cut end surfaces.
In Japanese Patent Application Laid-Open No. 2007-88232, the process of applying a resist to the cut end surfaces of the printed circuit board is provided after the printed circuit board is cut. This may increase manufacturing effort and manufacturing costs.